L-Acoustics MTD 112, Owner'S Manual

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MTD 112 24 06/97
4.2 THE MTD 112 LLCa CONTROLLER
a) Functions
The MTD 112 LLCa controller performs the following functions:
* Band rejection :
The frequencies that cannot be reproduced by the system are
rejected, i.e. below 50 Hz (in "Front" configuration) and above 20 kHz.
* Filtering :
Filtering functions are provided at 110 Hz for X.OVER configuration and on
the "sub" channel.
* Equalization :
The unit equalizes the frequency responses of the drivers/enclosure
assembly. The EQ functions are of the parametric type, especially designed for minimum
phase alteration. The EQ does vary according to the selected configuration in the L.F.
range.
* Limitation : The unit takes the power amplifier in a global feedback loop, using the output
of the amplifier to control VCAs limiting the output of the unit . The control signal is derived
from the "sense return" path.
2 limitations functions are provided: - cone excursion limitation for the L.F. driver
- thermal limitation for the L.F. and the H.F. drivers
These functions are carefully adjusted for minimum audible effect and thorough driver
protection.
* Mono summation: The inputs of two MTD 112 LLCa controllers are summed to derive a
mono signal capable of driving a central source. This mono signal can be the simple sum of
the inputs, for driving a central broad-band source, or can be filtered for driving a central
subwoofer.
b) Synopsis